Extraction of soluble products from wood



Jan. 1925- 1,523,578

v. BREDLIK ET AL EXTRACTION OF SOLUBLE PRODUCTS FROM WOOD Filed. May 51, 1921 IIL ll IL J=il:

J/Ecrm =5 /0 Air Compressor? arm %'cuum [am o Eff/ac for INVENTORS. VLADIMIR fiREDL/K.

y Laws C. Vl/fl/ ran; JR.

Patented Jan. 20, 1925.

UNITED STATES VLADIMIR BREDLIK AND LOUIS 0.

WHITON, JR., OF NEW YORK, N. Y.

EXTRACTION OF SOLUBLE PRODUCTS FROM Application filed May 31, 1921. Serial No. 478,805.

To all'whomitmay concern.- 7

Be it known that we, Vmnmm Bnnnmx, a citizen of the Republic of Czechoslovakia residing in the city, county, and State of a New York, and Lows C. Wmmx, Jr.,acitizen of the United States, residing m the city, county, and State of New York, have invented certain new and useful Improvements in the Extraction of Soluble Products 10 from Wood, of which the following is a specification.

In the seplag'ation of rosin, pine oil and turpentine m woods bearing these substances, such as cut pine, pine stumps, light 1!! wood, light tops, fir and spruce, the most common method involves steaming the wood to eliminate the volatile products and then extracting the soluble constitutents with gasoline, heated in a vessel which is closed or nearly closed so as to maintain the pressure n to secure the required temperature. The cat involved in this and other pr pnroduces certain decomposition products w 'ch contaminate the turpentine,

and produces an inferior quality of rosin and pine oil, probably also on account of the decomposition products and certain products which are soluble in a hot solvent but not in a cold one.

By our process the tern rature is or may be kept so low as to avoid these disadvantages and the products obtained are clear and transparent anlipractically the same as the commercial p ucts produced from the as gum directly. Our process also extracts a greater quantity of the constitutents from w so solvent is app ied. Under the reduced pressure a certain amount of air or rs released from the wood and hub les rise through the solvent, stirring up the matethan waspossi-ble under the previous rial in the pores and cells of the wood so as to increase the extraction. Preferably we start, after applying the solvent to the wood, with a pressure considerably above atmosp heric, and finish at atmospheric pressure.

he solubility of the constitutents in the wood is directl increased by reason of the pressure. We ave found that with this application of pressure we do not have to disintegrate the wood to the same extent as is necessary without pressure, nor do we have to use as large a quantity of solvent to treat a given quantity of wood. The chipping of the wood into small chips is disadvantageous because it renders the mass diflicult to work, and because the wood, after extraction is comparatively useless in making paper.

Following are examples of our proces. A preliminary air pressure is applied to the wood before the solvent is introduced, such preliminary pressure being from to pounds per square inch above atmospheric. The solvent is then applied and the pressure raised to 100 pounds per square inch above atmospheric pressure. The pressure is applied mechanically in contradistinction to pressure caused by heating the solvent and throttling down the vapor outlet. The pressure may, for example, be obtained by the application of airv ressure above the surface of the solvent orb tainer with solvent and pumping 1n solvent at an increased pressure. After a suitable interval, depending on the character of the solvent and of the wood, the pressure is relieved and restored to atmospheric. The preliminary pressure causes the air in the wood to be put -under pressure before the application of the solvent; and when the pressure is finally restored to atmospheric,

y filling the con the air thus initially compressedis liberated and disturbs the materials in the wood and exposes them more fully to the action of the solvent.

Or the solvent may be introduced at atmospheric pressure and the pressure he then increased to about 100.pounds per square inch above atmospheric, and releasedafter a suitable interval. This process does not subject the air in the wood to pressure until after the solvent is applied,but it produces approximately the same excellent results.

' third method consists in first applying the solvent, increasing the pressure to about 100 pounds above atmospheric and after a time relieving the pressure and further bringing it down to a point below atmos pheric, that is to a partial vacuum. This results in drawing air out of the wood which was held therein under atmospheric pressure, and is analogous to the first example given above in which the air and the wood was first compressed to a pressur greater than atmospheric.

In practice the relief of the pressure is accom lished by opening communication to a con enser so as not to waste the solvent vapors. After the release of the pressure the solvent is drained 01? and subjected to any usual or suitable process for separating the solvent, turpentine, pine oil and rosin. The wood from which the solvent has been removed will generally be subjected to a succession of treatments with solvent until the extraction has been accomplished to the extent commercially desirable.

An example of the working of the process is as follows: 100 parts of resin-bearing wood chips are charged into a suitable container capable of withstanding pressure. An air pressure of 35 lbs. per sq. in. is introduced into the vessel, and 120 arts of benzol, or a sufficient quantity to ]ust immerse the wood at atmospheric temperature, is umped into the tank, the pressure gradua 1y increasing as the air in the tank becomes compressed. In case the pressure has not reached 100 lbs, compressed air is added to bring it to this. After a period of 10 minutes the air pressure is relieved through a condenser or absorbent tower so as not to lose the benzol vapors contained in the air. If the cover is taken off the pressure tank, it will be noticed that bubbles arise to the surface of the liquid.

The wood is then washed three times with one-fifth of the original quantity of benzol each time to remove the solution of resinous material, and the residual benzol in the wood is recovered by steaming it. The degree of extraction will depend upon the character of the wood treated but will be considerably increased over that obtainable b simple washes of benzol. As an examp e of this: Treatment of the wood in exactly the same manner as described above with the exception that atmosphere pressure is maintained throughout the operation left 6.5% resinous matter in the extracted wood chips; when treatment of the same variety of wood was accomplished in the manner as described above, there remained 2.1% resinous matter in the extracted wood.

Our process provides a practical method of applying a solvent to wood without any preliminary steaming, without the application of so high a temperature as to injure the quality of the extracted constituents, with the possibility of using the wood in comparatively large pieces and with economy in the quantity of solvent used per ton of wood. I

The accompanying drawing is a diagrammatic representation of an apparatus suitable for carrying out the process.

As will be apparent from the several legends on the drawing the application comprises in addition to the extractor, an air compressor and vacuum pump, a solvent pump and a solvent reservoir. The wood chips are placed in the extractor through the upper door 1 to about the level 2, resting on a perforated bottom 3. Compressed air is first pumped ihto the extractor by opening valves 4 and 5, say to a pressure 0 thirty-five to fifty pounds per square inch above atmospheric pressure. Valves 6 and 7 are then opened and the air compressor raises the pressure both in the extractor and in the solvent tank; the valve 6 opening the way to the solvent tank. The valves 4 and 7 are then closed, leaving the valve 6 open. Also the valves 8 and 9 are opened to allow a circulation through the extractor and the solvent tank without loss of pressure and the solvent will flow by gravity from the tank into the extractor until the material in the latter is entirely submerged in the solvent. Leaving the valve 6 open, and again opening the valves 7 and 4, the pressure is increased on the solvent sayto 100 pounds per square inch above atmos heric pressure; and the amount of pressure being controlled by the air compressor.

When the solvent has been left in contact with the wood for a sufficient length of time the pressure is relieved by opening the valve 10.

This ap aratus is substantially the same as that 11 ustrated in connection with our Patent No. 1,372,47 9 of March 22, 1921, for the extraction of fatty matter from garbage and other fat containin materials. The filling and emptying of -t e extractor and the application of the solvent and the variations of pressure thereon may be (iffected in different ways and described in the aforesaid patent. And it will be understood that this apparatus is only ty ical of many arrangements of extractor, so vcnt tank and pumps and pipes which maybe used to carry out the process. The steam inlet shown is for initially eliminating the more volatile products, whenever this is desirable.

Though we have described with great particularly of detail certain specific processes embodying our invention, yet it is not to be understood therefrom that the invention is restricted to the particular e'amsle given.

Various modifications thereof in etail can be made by those skilled in the art without departure from the invention as defined in the following claim.

What we claim is:

In the extraction of soluble constituents from wood, the method which consists in applying a preliminary air pressure above atmospheric to the cells of the woocl applying a volatile solvent and subjectmg the sa rr1e to additional pressure without other- 10 wise increasing Its temperature and after a. suitable interval of time relieving the pressure.

In witness whereof, we have hereunto signed our names.

VLADIMIR BBEDLIK. LOUIS C. WHITON, JR. 

